PL238657B1 - New acid ionic liquids with 1-alkyl-1-methyl-4-hydroxypiperidinium cation and anion derived from 4-chloro-2-methylphenoxyacetic acid, method of their preparation and use as herbicides - Google Patents

Description

Description of the invention

The subject of the invention is new ionic liquids with a 1-alkyl-1-methyl-4-hydroxypiperidinium cation and an anion derived from 4-chloro-2-methylphenoxyacetic acid, their preparation and use as herbicides.

The following may be mentioned as examples of 1-alkyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetates:

• 1-hexyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate, • 1-methyl-1-octyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate, • 4-chloro-2-methylphenoxyacetate 1 - decyl-1-methyl-4-hydroxypiperidinium, • 1-decyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate, • 1-methyl-1-tetradecyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate • 1-hexadecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

The term "ionic liquids" (ILs) refers to chemical compounds with an ionic structure that exist in a liquid state at a temperature less than 100 ° C. By selecting ions with an appropriate chemical structure, it is possible to change the properties of a given ionic liquid, i.e. density, viscosity, melting point, water solubility and miscibility with other compounds. The first to describe and publish a work on low-melting organic salts was Schall in 1908, but intense interest in this class of compounds began after 1998. Ionic liquids meet three of the twelve existing green chemistry principles, i.e. the fifth principle, which is that safe solvents produce little waste and can be used repeatedly. The sixth rule that determines that they are energy efficient is to increase the efficiency and selectivity, when low temperature ionic liquids are used, the processes can be carried out at room temperature, and the ninth rule which determines the use in catalytic reactions.

4-Chloro-2-methylphenoxyacetic acid (MCPA) is a preparation commonly used in agriculture as an agent for controlling dicotyledonous weeds in cereal crops and in orchards and unused agricultural lands. The weeds sensitive to the action of MCPA include i.a. field mustard, weed radish, common steak, self-seeding rapeseed, white quinoa, field and sand poppy seeds. The herbicide is taken up primarily by the leaves of the plants and transferred to the growth tips. It is rapidly biodegradable and has not been found to have an unacceptable effect on the terrestrial and aquatic environment.

Herbicidal ionic liquids are compounds containing an ion with a herbicidal effect and a counterion with surface-active properties, and due to their properties they can be an alternative to herbicides currently available on the market. By selecting the appropriate cations and anions, it is possible to obtain a compound with the desired physicochemical properties. The main advantage of herbicidal ionic liquids is the immeasurable vapor pressure, therefore the risk of damage to non-target plants by evaporation of the active substance is limited. Moreover, in most cases they show a higher effectiveness of action compared to commercial herbicides, which enables the use of lower doses.

The present invention relates to new ionic liquids with a 1-alkyl-1-methyl-4-hydroxypiperidinium cation and a 4-chloro-2-methylphenoxyacetate anion of the general formula I, in which R represents an alkyl substituent of 6 to 16 carbon atoms in length. The method of their preparation consists in dissolving the 1-alkyl-1-methyl-4-piperidinium bromide of the general formula 2, in which R is an alkyl substituent with a length of 6 to 16 carbon atoms, is dissolved in methanol or in ethanol or in 2-propanol or in water, then chemically reacted with the lithium or sodium or potassium salt of 4-chloro-2-methylphenoxyacetic acid of the general formula 3, in which M + is a lithium or sodium or potassium cation at a temperature of from 15 ° C to 40 ° C, preferably 25 ° C, and for at least 15-40 minutes, preferably 20 minutes, then the precipitate is filtered off, the solvent is evaporated further, the residue is dried, and after reacting in water, the residue is washed with anhydrous an organic solvent from the group: acetone or acetonitrile or chloroform.

The use of new ionic liquids as herbicides.

It is advantageous when the ionic liquids are used in the form of an aqueous solution with a concentration of 0.1-5% of the active ingredient.

Thanks to the solution according to the invention, the following technical and economic effects were obtained:

• a method of obtaining new ionic liquids was developed,

• syntheses carried out according to the developed method are carried out without additional energy expenditure at room temperature with high efficiency reaching 95%, • high purity products up to 99% are obtained during the synthesis, which is confirmed by analytical methods, • the obtained ionic liquids are well soluble in polar protic solvents such as water, methanol, isopropanol and DMSO, the obtained compounds show herbicidal activity against dicotyledons and are selective for most monocotyledons.

The method of producing herbicidal ionic liquids is shown in the following examples: Example I

Method for the production of 1-hexyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

A solution of 0.008 mol (2.24 g) of 1-hexyl-1-methyl-4-hydroxypiperidinium bromide in 40 cm ^{3 of} 2-propanol was added to the flask equipped with a magnetic stirrer, followed by the addition of 0.0088 mol (1.96 g) 4 sodium chloro-2-methylphenoxyacetate. The reaction was carried out under constant stirring for 20 minutes, keeping the system temperature constant at 25 ° C. Thereafter, the precipitated inorganic precipitate was filtered off, and the solvent was then evaporated using a rotary vacuum evaporator. The crude product was dried under reduced pressure. The reaction yield was 93%.

Based on the analysis of carbon and proton nuclear magnetic resonance spectra, the structure of the obtained ionic liquid was confirmed: 1H NMR (300 MHz, DMSO-d6) δ [ppm] = 0.87 (t, J = 6.72 Hz, 3H), 1.28 (m, 6H), 1.64 (m, 2H), 1.71 (m, 2H), 1.96 (m, 2H), 2.14 (s, 3H), 3.00 (d, J = 6.46 Hz, 3H), 3.29 (m, 4H), 3.42 (m, 2H), 3.76 (m, 1H), 4.13 (s, 2H), 6.66 (d, J = 8.73, 1H), 7.07 (dd, J = 8.73; 2.71 Hz, 1H), 7.13 (d, J = 2.71 Hz, 1H). ¹³ C NMR (75 MHz, DMSO-d ₆ ) δ [ppm] = 13.5; 15.6; 20.6, 21.6; 23.8; 25.7, 30.7; 46.2; 56.2; 60.5; 67.9; 112.4; 122.0; 125.4, 127.3; 128.9; 155.7; 169.3.

Elemental CHN analysis for C21H34CINO3 (Mmol = 399.96 g / mol): calculated values (%): C = 63.06; H = 8.57; N = 3.50; measured values: C = 63.41; H = 8.19; N = 3.32.

P r x l a d II

Method for the production of 1-octyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

A solution of 0.014 mol (4.32 g) of 1-octyl-1-methyl-4-hydroxypiperidinium bromide in 40 cm ^{3 of} methanol was introduced into the flask equipped with a magnetic stirrer. Then 0.014 mol (3.34 g) of potassium 4-chloro-2-methylphenoxyacetate was added. The reaction was carried out under continuous stirring for 40 minutes at a temperature of 15 ° C. Thereafter, the precipitated potassium bromide was filtered off and the methanol was evaporated off using a vacuum evaporator. The product was dried under reduced pressure. The reaction yield was 92%.

Carbon and proton nuclear magnetic resonance spectra were made, on the basis of which the structure of the obtained salt was confirmed: 1H NMR (300 MHz, DMSO-d6) δ [ppm] = 0.86 (t, J = 6.70 Hz, 3H), 1, 27 (m, 10H), 1.64 (m, 2H), 1.71 (m, 2H), 1.95 (m, 2H), 2.14 (s, 3H), 3.00 (d, J = 6.47 Hz, 3H), 3.29 (m, 4H), 3.42 (m, 2H), 3.76 (m, 1H), 4.14 (s, 2H), 6.66 (d , J = 8.73, 1H), 7.07 (dd, J = 8.73; 2.71 Hz, 1H), 7.13 (d, J = 2.71 Hz, 1H). ¹³ C NMR (75 MHz, DMSO-d6) δ [ppm] = 13.5; 15.6; 20.6, 21.6; 25.4, 26.9; 27.3; 28.1; 30.7; 46.2; 56.2; 60.5; 67.9; 112.4; 122.0; 125.4, 127.3; 128.9; 155.7; 169.3.

Elemental CHN analysis for C23H30CINO3 (Mmol = 428.01 g / mol): calculated values (%): C = 64.54; H = 8.95; N = 3.27; measured values: C = 64.90; H = 9.17; N = 3.51.

P r z x l a d III

Method for the production of 1-decyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

In a flask equipped with a magnetic stirrer, 0.015 mol (5.05 g) of 1-decyl-1-methyl-4-hydroxypiperidinium bromide was placed in 50 cm ^{3 of} water. Followed by addition of 30 cm ^{3 of} an aqueous solution containing 0.015 mol (3.10 g) of 4-chloro-2-metylofenoksyoctanu lithium. The reaction was carried out under continuous stirring for 20 minutes at 40 ° C. Thereafter, the water was evaporated, and the residue was dissolved in 30 cm ^{3 of} acetone, and then the precipitate of the inorganic salt was filtered off. After evaporation of acetone, the crude product was dried under reduced pressure. The reaction yield was 95%.

The analysis of the obtained carbon and proton nuclear magnetic resonance spectra allowed to confirm the structure of the salt obtained: 1H NMR (300 MHz, DMSO-d6) δ [ppm] = 0.86 (t, J = 6.71

PL 238 657 B1

Hz, 3H), 1.27 (m, 14H), 1.64 (m, 2H), 1.71 (m, 2H), 1.95 (m, 2H), 2.14 (s, 3H), 3.00 (d, J = 6.47 Hz, 3H), 3.29 (m, 4H), 3.41 (m, 2H), 3.76 (m, 1H), 4.14 (s, 2H ), 6.66 (d, J = 8.74, 1H), 7.07 (dd, J = 8.73, 2.71 Hz, 1H), 7.14 (d, J = 2.71 Hz, 1H). ¹³ C NMR (75 MHz, DMSO-d6) δ [ppm] = 13.5; 15.6; 20.6, 21.6; 25.4, 26.9; 27.3; 28.1; 28.9; 29.0; 30.7; 46.2; 56.2; 60.5; 67.9; 112.4; 122.0; 125.4, 127.3; 128.9; 155.7; 169.3.

The content of cationic substances was determined by the two-phase titration method in accordance with the PN-EN ISO 2871-1 standard. Product purity was 99%.

P r x l a d IV

Method for the production of 1-dodecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

^{40 cm 3 of} water were placed in a flask equipped with a magnetic stirrer, then 0.01 mol (3.64 g) of 1-dodecyl-1-methyl-4-hydroxypiperidinium bromide was introduced and stirring was started. After dissolving the starting material, 0.011 mol (2.63 g) of potassium 4-chloro-2-methylphenoxyacetate was added to the system. The reaction was carried out under constant stirring for 20 minutes at a temperature of 20 ° C. Thereafter, the water was evaporated using a vacuum evaporator. The residue was dissolved in 30 cm ³ of acetonitrile in order to remove inorganic by-product. After the potassium bromide was filtered off, the solvent was evaporated and the residue was dried under reduced pressure. The finished product was obtained with a yield of 94%.

The structure of the obtained compound was confirmed by proton and carbon nuclear magnetic resonance analysis: 1H NMR (400 MHz, DMSO-de) δ [ppm] = 0.86 (t, J = 6.61 Hz, 3H), 1.24 (s , 18H), 1.62 (m, 2H), 1.74 (m, 2H), 1.93 (m, 2H), 2.15 (s, 3H), 3.00 (d, J = 6, 94 Hz, 3H), 3.31 (m, 4H), 3.43 (m, 2H), 3.78 (m, 1H), 4.15 (s, 2H), 6.68 (d, J = 8.82 Hz, 1H), 7.07 (dd, J = 8.67; 2.69 Hz, 1H), 7.11 (d, J = 2.06 Hz, 1H). ¹³ C NMR (100 MHz, DMSO-d6) δ [ppm] = 13.9; 16.0; 21.2, 22.1; 25.9, 27.4; 27.7; 28.6; 28.8; 28.9; 29.0; 31.4; 46.5; 56.5; 61.1; 68.3; 112.8; 122.5; 125.8; 127.8; 129.3; 156.2; 170.0.

Elemental analysis of CHN for C27H46CINO3 (Mmol = 484.12 g / mol): calculated values (%): C = 66.99; H = 9.58; N = 2.89; measured values: C = 66.63; H = 9.84; N = 3.21.

P r z k ł a d V

Method for the production of 1-tetradecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

To a reactor equipped with a magnetic stirrer a solution of 0.025 mol (9.81 g) bromide 1-tetradecyl-1-methyl-4-hydroksypiperydyniowego in 80 cm ³ of ethanol. Then 0.025 mol (5.16 g) of lithium 4-chloro-2-methylphenoxyacetate was added. The reaction was carried out under continuous stirring for 15 minutes at 40 ° C. Thereafter, the precipitated sodium bromide was filtered off and the ethanol was evaporated off using a vacuum evaporator. The crude product was then dried under reduced pressure. 1-tetradecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate was obtained in a yield of 94%.

The chemical structure of the obtained ionic liquid was confirmed by analyzing the obtained nuclear magnetic resonance spectra: 1H NMR (400 MHz, DMSO-de) δ [ppm] = 0.86 (t, J = 6.62 Hz, 3H), 1.24 ( s, 22H), 1.63 (m, 2H), 1.74 (m, 2H), 1.94 (m, 2H), 2.15 (s, 3H), 3.02 (d, J = 6 , 94 Hz, 3H), 3.31 (m, 4H), 3.44 (m, 2H), 3.78 (m, 1H), 4.16 (s, 2H), 6.68 (d, J = 8.83 Hz, 1H), 7.07 (dd, J = 8.67; 2.68 Hz, 1H), 7.11 (d, J = 2.05 Hz, 1H). ¹³ C NMR (100 MHz, DMSO-d6) δ [ppm] = 13.9; 16.0; 21.2, 22.1; 25.9, 27.4; 27.7; 28.6; 28.8; 28.9; 29.0; 29.1; 31.4; 46.5; 56.5; 61.1; 68.3; 112.8; 122.5; 125.8; 127.8; 129.3; 156.2; 170.0.

The content of cationic substances was determined by the two-phase titration method in accordance with the PN-EN ISO 2871-1 standard. Product purity was 97%.

P r x l a d VI

Method for the production of 1-hexadecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate

In a flask equipped with a stirrer provided 40 cm ^{3 of} an aqueous solution containing 0.012 mol (5.05 g) bromide, 1-hexadecyl-1-methyl-4-hydroksypiperydyniowego, was added 0.012 mol (2.67 g) of 4-chloro-2- sodium methylphenoxyacetate. The reaction was carried out under continuous stirring for 40 minutes at 25 ° C. Thereafter, water was removed from the system, and chloroform was added to the residue. The chloroform-insoluble inorganic salt was filtered off, and the solvent was removed from the filtrate. The obtained residue was dried under reduced pressure to obtain the finished product with a yield of 94%.

Carbon and proton nuclear magnetic resonance spectra were made, and the structure of the obtained compound was confirmed on the basis of the spectra obtained: 1H NMR (400 MHz, DMSO-de) δ

PL 238 657 Β1

[ppm] = 0.85 (t, J = 6.61 Hz, 3H), 1.24 (s, 26H), 1.62 (m, 2H), 1.74 (m, 2H), 1.94 (m, 2H), 2.15 (s, 3H), 3.01 (d, J = 6.94 Hz, 3H), 3.31 (m, 4H), 3.43 (m, 2H), 3 , 78 (m, 1H), 4.16 (s, 2H), 6.68 (d, J = 8.83 Hz, 1H), 7.07 (dd, J = 8.66, 2.68 Hz, 1H), 7.11 (d, J = 2.05 Hz, 1H). ¹³ C NMR (100 MHz, DMSO-c / β) δ [ppm] = 13.9; 16.0; 21.2, 22.1; 25.9, 27.4; 27.7; 28.6; 28.7; 28.8; 28.9; 29.0; 29.1; 31.4; 46.5; 56.5; 61.1; 68.3; 112.8; 122.5; 125.8; 127.8; 129.3; 156.2; 170.0.

The content of cationic active substances was determined by the two-phase titration method in accordance with PN-EN ISO 2871-1. Product purity was 96%.

Application example

Research on biological activity against weeds in greenhouse conditions.

The experiment was carried out under controlled greenhouse conditions (temperature: 20 ° C, humidity: 60%, lighting time day / night: 16/8 h). The test plant was winter oilseed rape (Brassica napus L). The seeds were sown in pots filled with soil to a depth of 1 cm from the surface. After producing the cotyledons, an interruption was made, leaving 5 plants in each pot. In the 4-leaf phase of the plant (BBCH 14), a treatment was performed with a cabin sprayer equipped with a TeeJet 110/02 VP sprayer, which moved over the plants at a constant speed of 3.1 m / s. The distance of the sprayer from the tops of the plants was 40 cm, the liquid pressure in the sprayer was 0.2 MPa, and the liquid output per 1 ha was 200 dm ³ .

Ionic liquids were used in the form of aqueous solutions in the amount corresponding to 400 g of MCPA anion per 1 ha. Two commercial herbicides containing MCPA in the form of sodium-potassium salt (Chwastox Extra 300 SL, 300 g sc in 1 dm ^{3 of the} preparation) and in the form of an ester (Chwastox AS 600 EC, 600 g sc in 1 dm ³ of the preparation) were used as comparative measures. ). The percentage of active ingredient was 0.1-5%.

Three weeks after treatment, the plants were cut at the soil surface and weighed, on this basis the reduction in fresh weight compared to the control was determined. The study was performed in four repetitions in a completely randomized design.

Table 1 shows the efficacy of 4-chloro-2-methylphenoxyacetates

Table 1

Object No. The name of the measure Fresh weight reduction (%) 1 4-chloro-2-m ethylphen o xyacetate n 1-he xyl o-l-m ethyl-4-hydroxypiperidinium 26 2 4-chloro-2-m ethylpheno n-1-methyl-1-octyl-4-hydroxypiperidinium xyacetate 44 3 1-decyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate 40 4 1-dodecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate 54 5 1-Methyl-1-tetradecyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate 57 6 1-hexadecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate 57 7 Chwastox Extra 300 SL {reference preparation 1) 22 8 Chwastox AS 600 EC (reference preparation 2) 33

The results of the conducted research indicate high biological activity of most of the tested ionic liquids. The effects of destruction of winter oilseed rape plants were dependent on the length of the alkyl substituent in the cation structure. Two ionic liquids with the longest alkyl chains have been found to work very well: 1-tetradecyl-1-methyl-4-hyaline 4-chloro-2-methylphenoxyacetate

Droxypiperidinium and 1-hexadecyl-1-methyl-4-hydroxypiperidinium 4-chloro-2-methylphenoxyacetate. These compounds showed twice the effectiveness of the action than the commercial preparation containing the sodium-potassium salt of MCPA and the efficiency by 24% higher than the preparation containing the MCPA ester form.

Claims (4)

1. New ionic liquids with a 1-alkyl-1-methyl-4-hydroxypiperidinium cation and a 4-chloro-2-methylphenoxyacetate anion of the general formula I, in which R is an alkyl substituent with a length of 6 to 16 carbon atoms. The method of obtaining herbicidal ionic liquids according to claim 1, characterized in that 1-alkyl-1-methyl-4-piperidinium bromide of the general formula 2 in which R is an alkyl substituent of 6 to 16 carbon atoms in length, is dissolved in methanol, either in ethanol or in 2-propanol or in water, then chemically reacted with a lithium or sodium or potassium salt of 4-chloro-2-methylphenoxyacetic acid of general formula 3, where M ⁺ is a lithium cation, or sodium or potassium, at a temperature from 15 ° C to 40 ° C, preferably 25 ° C, and for at least 15-40 minutes, preferably 20 minutes, then the precipitate is filtered off, the solvent is further evaporated and the residue is dried, and after After carrying out the reaction in water, the residue is washed with an anhydrous organic solvent from the group: acetone or acetonitrile or chloroform. 3. Use of the new ionic liquids defined in claim 1 as herbicides. 4. Use according to claim 1 The method of claim 1, characterized in that the ionic liquids are used in the form of an aqueous solution with a concentration of 0.1-5% of the active ingredient.